The studies carried during the project revealed the significant effect of magnetic topology on SEP production of the active regions. It could be related not only with acceleration processes but with the process of particle escaping from the solar atmosphere to interplanetary space. However, the unambiguous indicator is difficult to find. One possible approach is testing for the breaking of the classical sunspot group evolution laws (Hale's law, Joy's law, etc.) using technique suggested by Abramenko et al. (2018). Based on the study of the set of flare occurred within 2001–2005 and related with strong proton event, we found that 'the right' active regions support the relationships characterizing the acceleration processes in solar flares. But most of the active regions related to SEP events broke at least one of the law and did not show any relationships with traditional indicators of acceleration processes. This kind of study should be done on more statistical representative data set for 23 and 24 solar cycles.
We show in the paper by Kashapova et al. (2019) that analysis of SEP events related with solar flares from the same active region (AR) could be useful for testing of approaches used for the statistical study of the relationship between this two phenomena. The next studies should be carried out based on events occurred in AR existing more than one rotation of the Sun. Such ARs was used for the study of flares with quasi-periodic pulses by Pugh et al. (2019). NOAA 12172/12192/12209 existed on solar disk from September to November 2014. The AR could be also used for the study also of SEP events related to solar flares.
As it was shown by Myshyakov et al. (2018 and 2019 subm.) the index decay distribution above the polarity inversion line (PIL) could indicate to the potential eruption of quiet filaments located out of ARs. This class of filaments (prominences) are usually not taking into account however their eruption could be related to geoeffective events. We should analyze the decay index distribution above PIL between ARs related to filaments and it is a relation to SEP events. We could use results by Tsvetkov et al. (2018) as initial data set.
Alternative solar origin associations do lead to different values for the correlation coefficients according to Miteva (2019). The effect is more pronounced when the sample is small, so the weight of the difference becomes larger. The difference is stronger when the correlations with flare class but also flare fluence are considered. Thus, alternative solar origin associations and small event sample could be reasons for the usually lower correlation coefficients reported with flares, compared to CMEs, especially when using NOAA and GOES based solar origin associations or catalogs. CME kinetic energy gives consistent results to those when using CME speed, since either can be regarded as a representative parameter of the CME proton acceleration and the two parameters are interdependent. The use of flare fluence over class usually improves the correlations, however this trend is specific to the event sample − both in origin and size − and to the time-period under consideration. Thus the observer subjectivity still plays an decisive role in the SEP analysis and their interpretation, since a chain of specific choices is made that are instrument, time and observer specific, namely selecting which type of flare or CME parameter to be used for the analysis, the time coverage under investigation, the way of association between SEPs and flares/CMEs, and the final sample size.
References
Kashapova L., Miteva R., Myagkova I., Bogomolov A. Characteristics of SEP Events and Their Solar Origin During the Evolution of Active Region NOAA 10069 (2019) Solar Physics, Vol. 294: 9 [DOI:10.1007/s11207-019-1400-3]
Myshyakov I., Tsvetkov Ts., Petrov N. Comparison of kinematics of the solar eruptive prominence and spatial distribution of the magnetic decay index (2018), Proceedings of Tenth Workshop "Solar Influences on the Magnetosphere, Ionosphere and Atmosphere" Primorsko, Bulgaria, June 4÷8, 2018 pp. 109–113
Myshyakov et al. (2019), subm.
Tsvetkov Ts., Miteva R., Petrov N. On the relationship between filaments and solar energetic particles (2018), JASTP, Vol.179, Pages 1–10 [DOI:10.1016/j.jastp.2018.06.005]
Miteva R. On the solar origin of in situ observed energetic particles (2019), Bulgarian Astronomical Journal, Vol. 31, pp. 51–67
Abramenko et al. (2018) Geomagnetism and Aeronomy, Volume 58, Issue 8, pp.1159-1169 [DOI 10.1134/S0016793218080224]
Pugh et al. (2019) Astronomy & Astrophysics, Volume 624, id.A65, 11 pp. [DOI 10.1051/0004-6361/201834455]
